Installing an openATTIC Multi-node System

openATTIC can be installed in a multi-node setup, in which any node can be used to manage the whole system and commands are distributed to the appropriate node automatically. This is implemented by using a shared configuration database, connecting all openATTIC nodes to the same PostgreSQL database.

This is usually the database of the first node that you have installed and configured, but can be a database running on a dedicated node, too.

In order to use DRBD®, you will need to set up a multi-node setup consisting of two hosts.

Note

Note that multi-node support currently applies to the “traditional” storage management functionality of openATTIC only. For managing Ceph, you need to connect to the web interface of the openATTIC node configured to connect to the Ceph cluster directly.

Step 1 - Install Two openATTIC Hosts

In the following example the first host is called openattic01.yourdomain.com (IP address: 192.168.1.101) and the second openattic02.yourdomain.com (IP address: 192.168.1.102). Both hosts should be able to connect to each other using their host names, so make sure that DNS is configured correctly (or you have configured /etc/hosts accordingly on both nodes).

Note that these two systems don’t necessarily need to have the exact same specifications (e.g. hardware, hard disks). However, the version of openATTIC and the operating system (and particularly the Django version) running on these hosts must be identical.

In the example below, Debian Linux is assumed as the operating system. The path names to configuration files and some configuration details (e.g. PostgreSQL or firewall configuration) might differ on other platforms.

As a first step, you should setup and install these two openATTIC hosts as described in Installation and Getting Started.

Note

You should only perform the Post-installation Configuration on one of the two hosts for now! This example assumes that the command was executed on host openattic01, which will result in the installation of the entire openATTIC system including the configuration database on that node.

Step 2 - Database Configuration on openattic01

Next, the PostgreSQL database configuration on openattic01 needs to be adjusted so it accepts incoming remote connection attempts from openattic02.

Edit the /etc/postgresql/<VERSION>/main/postgresql.conf and /etc/postgresql/<VERSION>/main/pg_hba.conf configuration files on openattic01.

Note

The location of these files might be different on other Linux distributions.

First, set the correct listen addresses within the postgresql.conf file. Add openattic01‘s external IP address to listen_addresses and uncomment this configuration setting:

#------------------------------------------------------------------------------
# CONNECTIONS AND AUTHENTICATION
#------------------------------------------------------------------------------

# - Connection Settings -

listen_addresses = 'localhost, 192.168.1.101'  # what IP address(es) to listen on;
                                 # comma-separated list of addresses;
                                 # defaults to 'localhost'; use '*' for all

Note

On some operating systems, the firewall configuration might prevent external communication requests to the TCP port used by PostgreSQL (5432 by default). Please consult your distribution’s documentation on how to configure the firewall to accept incoming connections from openattic02 to this port.

Next, you need to add openattic02 to PostgreSQL’s client authentication configuration file pg_hba.conf. Edit the file and add the following line to the IPv4 local connections section as follows:

# IPv4 local connections:
host    all             all             127.0.0.1/32            md5
host    openattic       openattic       192.168.1.102/32        md5

This ensures that PostgreSQL accepts authentication requests to the local openattic database from the remote host openattic02.

You need to restart the PostgreSQL service on openattic01 afterwards, to apply these settings:

# systemctl restart postgresql

Step 3 - Remote Database Configuration on openattic02

Since openattic02 needs to connect to the database of openattic01 you will have to enter the database information (database name, user, password and host) from openattic01 into the database configuration file /etc/openattic/database.ini on openattic02 manually. The password can be obtained from the database.ini file on openattic01. The username and database name are openattic by default.

The database.ini file on openattic02 should look something like this:

[default]
engine   = django.db.backends.postgresql_psycopg2
name     = openattic
user     = openattic
password = <password>
host     = openattic01.yourdomain.com
port     =

Step 4 - Execute oaconfig install on openattic02

Now that you have configured openattic02 to connect to the database running on openattic01, you can conclude the Post-installation Configuration on openattic02 by executing oaconfig install there.

If everything worked out well, you should now see both openattic01 and openattic02 in the Hosts tab of the web UI running on openattic01 (and openattic02 respectively), as well as the disks, pools and volumes of both hosts.